(Sr,Ca)_4Si_3O_8Cl_4基质中Eu^(2+)的发光特性研究  

Study on Luminescence Properties of Eu^(2+) in(Sr,Ca)_4Si_3O_8Cl_4 Host Lattice

作　　者：孙家跃[1] 夏志国[1] 杜海燕[1] 

机构地区：[1]北京工商大学化学与环境工程学院,北京100037

出　　处：《光谱学与光谱分析》2005年第11期1760-1763,共4页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金(20476002);北京市自然科学基金(2042007)资助项目

摘　　要：采用高温固相法合成Sr4-xCaxSi3O8Cl4:Eu2+荧光材料,利用Van Uitert公式讨论Sr4-xCaxSi3O8Cl4:Eu2+中yEu2+的晶格环境和发光特性,确定晶体中有蓝色和黄绿色两种发光中心,并讨论了它们与光谱结构的对应关系。当0<x<0.5,Ca2+固溶入Sr4Si3O8Cl4基质晶格,Eu2+占据八配位Sr2+格位,晶体主要产生蓝色中心的蓝绿色发射;当0.5<x<2,较大的Ca2+掺杂使晶胞参数变小,晶格中的杂质束缚激子态的束缚增强,Eu2+处于杂质束缚激子中心所形成的激发态能量进一步降低,发射位于长波段方向并具有较大的Stokes位移,Sr4-xCaxSi3O8Cl4:yEu2+主要产生黄绿色中心的黄绿色发射光。Alkali earth chlorosilicate of the type Sr4-xCaxSi3O8Cl4 was synthesized through the high temperature solid state method. According to the Van Uitert experimental equation, luminescence properties and crystal-lattice environment of Eu^2＋ in Sr4-x CaxSi3O8Cl4 crystal were discussed. The possibilities of two Eu^2＋ emission centers, viz. blue and greenish-yellow centers, were found and their corresponding relationships with spectra were also discussed. When the doping amount of calcium（x） varied between 0 and 0.5, Ca^2＋ ions were embedded in the host lattice of Sr4Si3O8Cl4, and the luminescence of blue center, which was ascribed to the emission of Eu^2＋ that substituted the octa-coordination Sr^2＋ sites, dominated and showed blue-green luminescence. Sr4-xCaxSi3O8Cl4：yEu^2＋ exhibited greenish-yellow luminescence when the range of x was between 0.5 and 2. This was due to the fact that the Eu^2＋ emission originated from the formation of an impurity-trapped exciton state. Greenish-yellow emission center was located in the impurity-trapped exciton state which was the lowest excited state of this system, and the Eu^2＋ emission was at long wavelengths, and a large Stokes shift was observed.

关 键 词：光谱 发光 氯硅酸盐 基质晶格 杂质束缚激子 

分 类 号：O482.3[理学—固体物理]